Based on research results obtained on partially implantable middle ear hearing assistive device, a three year multidisciplinary research is proposed with the objectives to improve the design, to fabricate prototype implant units, and to evaluate these units in acute and chronic animals, to determine the feasibility for implant study in human volunteers. A partially implantable middle ear hearing assisting system was designed by the investigators in collaboration with a medical device manufacturing industry. The design has an external unit that converts the sound into modulated radio frequency signal transmitted to the implant unit which converts the signal into vibration coupled to the ossicular chain for hearing. The significant and unique approaches of the system are: (a). non-contact electromagnetic coupling of vibration from the device to ossicular chain; (b). no bias force on the ossicular chain when the device is idling, by using special air core coil; (c). no battery in the implant unit to limit the life of the device; (d). all electronics and the coil are hermetically encapsulated in Titanium to prevent corrosion and degradation during the life time; all materials in contact with the body are biocompatible and is expected to have indefinite life; and (e). the implant unit is miniaturized and manufacturable with existing fabrication technology. The specific aims of the proposed research are: (a). to characterize the performance of the designed hearing assisting system in laboratories with engineering instruments and test it in experiments on acute animals and human temporal bones. Necessary tools for implant operation will be developed to insure that the implant will have consistent and desired performance; (b). to evaluate the implant device and the total system in acute and chronic animals, to identify any parts that need improvement and to determine the expected life time of the implant device and the total system; (c). to study the physiology of the ossicular chain with acute and chronic animals; (d). to determine the feasibility of the device for human implant and to modify the system for future evaluation on human volunteers.